Wavelength division multiplexing (WDM) is one technology that is envisioned to increase bandwidth capability and enable bidirectional communications in optical networks. In WDM networks, multiple data signals can be transmitted simultaneously between network elements (NEs) using a single fiber. Specifically, the individual signals may be assigned different transmission wavelengths so that they do not interfere or collide with each other. The path that the signal takes through the network is referred to as the lightpath. One type of WDM network, a wavelength switched optical network (WSON), seeks to switch the optical signals with fewer optical-electrical-optical (OEO) conversions along the lightpath, e.g. at the individual NEs, than existing optical networks.
One of the challenges in implementing WDM networks is the determination of the routing and wavelength assignment (RWA) for the signals transported along the path. The path assignment may be implemented separately by a path computation element (PCE) while the wavelength assignment may be distributed among the NEs along the path. However, the NEs along the path may comprise NEs with wavelength conversion capabilities. Such information, in addition to other wavelength assignment or availability information, may be used for determining whether to implement a wavelength conversion along the path in a distributed wavelength assignment scheme.